Method for preparing water-based acrylic resin by continuous extrusion process and production equipment for realizing the method

Abstract

The invention provides a method for preparing water-based acrylic resin by a continuous extrusion process. The method adopts a loop reactor and a twin-screw extrusion reactor in series as a continuous reactor. First, the monomer, the initiator and the optional The molecular weight regulator is sucked from each raw material barrel into the mixed raw material preparation tank under negative pressure, and then the material in the preparation tank is sent to the loop reactor at a temperature of 120°C at a rate of 50-150kg / hour by a feeding pump The residence time of the material in the loop reactor is 15 minutes. After the material enters the twin-screw extrusion reactor, the screw speed is controlled to be 20-50 rpm, and the valve of the devolatilization section is opened to make the material undergo vacuum desorption in the third section. Volatilize, and the devolatilized product is granulated and dried under water at a temperature below 30°C, and then packaged after passing through a cyclone separator. The water-based acrylic resin prepared by the method of the invention has the characteristics of good quality stability, large molecular weight and narrow distribution. The present invention also provides a production device for realizing the above method.

Description

technical field [0001] The present invention relates to a preparation method of acrylic resin, in particular to a preparation method of water-based varnish, water-based printing ink, water-based wood varnish or water-based industrial paint, and more particularly to a continuous extrusion process Method for preparing water-based acrylic resin. The present invention also provides a production device for realizing the above method. Background technique [0002] In 1988, Johnson Corporation of the United States invented water-based acrylic resin as an emulsifier for water-based varnish emulsions, water-based printing ink emulsions (binders) and dispersion resins for water-based ink colorants. use. Water-based acrylic resin is polymerized from styrene, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid or acrylic acid with high gloss and high hardness, and the main chain is a strong hydrophobic structure , the side groups are ester groups and ca...

AI Technical Summary

Problems solved by technology

[0004] The advantages of the solution polymerization method are: ① The requirements for equipment are not high, and it can be realized by free radical polymerization at atmospheric pressure; ② The molecular weight and its distribution are controlled stably; ③ No special material transfer pump is required; its fatal disadvantage is: when the production scale After exceeding 1500L, how to remove the residual solvent (ethylene glycol or propylene glycol monoether solvent) to less than 1%, if the residual alcohol ether solvent is too large, it is difficult to be used as water-based varnish, water-based printing ink binder— —The emulsifier in the emulsion polymerization process of acrylic copolymer can only be used as the dispersing resin in the process of ink grinding and color paste

[0006] At present, the process of producing water-based acrylic resin by bulk method mainly includes tubular reactor bulk polymerization method and three-pot series continuous bulk polymerization method. The disadvantage of using tubular reactor bulk polymerization method to produce water-based acrylic resin is that the monomer conversion rate must be close to 100. %, so in order to continuously remove the material from the reactor, the temperature of the reactor must be maintained at 270-300°C. Even so, it can only produce water-based acrylic resin with a weight average molecular weight below 10000Da, but cannot produce a weight average molecular weight of more than 10000Da resin, otherwise the material cannot be transported and flowed

The continuous mass polymerization of three reactors in series is the mainstream method at present, but the material transfer pump from the first reactor to the second reactor and the subsequent reactor (third reactor) is very expensive, and the pipeline pump body needs to be treated with temperature. The first disadvantage is that the design pressure of the tank reactor is as high as 7MPa, and the investment in equipment is large; in addition, the biggest disadvantage of the continuous bulk polymerization method with three tanks in series is that it is difficult to control the molecular weight and its distribution, especially in the subsequent tank stage, due to the high viscosity of the system, It is easy to produce auto-acceleration effect, and the addition of initiator and chain transfer agent cannot control this phenomenon, and excellent water-based acrylic resin should have a lower narrow molecular weight distribution, otherwise it will affect the rheological properties and color development of the emulsion binder sex

Images